A respirator for controlling the breathing gas flow in an anesthesia apparatus is known from DE 102 19 286 C1 (corresponding to U.S. Pat. No. 6,805,119 which is hereby incorporated by reference). The respirator comprises, in a layered structure, a breathing gas block, which is traversed by a plurality of gas ducts, a valve plate and a cover, with which the valve plate is braced in relation to the breathing gas block. The breathing gas block is provided with breathing gas ports, via which free breathing gas is supplied to the patient, on the one hand, and, on the other hand, the breathing gas expired by the patient is again taken up. The expired breathing gas is sent via an absorber cartridge, with which the carbon dioxide is removed from the expired gas. The breathing gas thus purified is subsequently supplied again to the patient during the next phase of inspiration. Directional valves in the valve plate ensure a directed breathing gas flow, which leads via an inspiration line to the patient and from the patient back into an expiration line. A breathing gas supply means, which generates the necessary inspiration pressure at the patient, is needed for transporting the breathing gas to the patient. This breathing gas supply means may be integrated in the respirator in the form of a blower, or it is connected to the respirator as a separate reciprocating pump.
A radial blower for supplying breathing gas in a closed breathing circuit is known from DE 101 61 821 C1 (corresponding to U.S. Pat. No. 7,281,538 which is hereby incorporated by reference). The radial blower comprises an upper part carrying breathing gas with a blower rotor (blower wheel or blower impeller), which transports breathing gas from a gas inlet to a gas outlet, and a drive motor, which sets the blower wheel into rotation. A coupling is located between the upper part and the drive motor to make it possible to separate the upper part from the drive motor for disinfection purposes and to connect it to the drive motor again later.
Even though the coupling is dimensioned such that the coupling parts can be reassembled without observing a preferred position, the coupling parts are subject to a certain wear due to the mounting and removal and are additionally stressed by pressure variations during the changeover from the phase of inspiration to the phase of expiration.